Density Straight vegetable oil Diesel engine Combustion a b s t r a c tThe straight use of vegetable oils as fuel in diesel engines entails adjusting several physical properties such as density and viscosity. By adequately heating the vegetable oil before entering the injection system, its physical parameters can reach values very close to that of diesel fuel. Consequently, by properly adjusting the temperature of vegetable oils used as fuel, it is possible to improve their combustion performance, thus avoiding premature engine aging due to incomplete burning. In this study the density and viscosity of several vegetable oils are studied within a wide variety of temperatures. The optimal range of temperatures at which each vegetable oil should operate in order to adjust its properties to those of automotive diesel and biodiesel is then found. Additionally an empirical relationship between the dependence of viscosity with density is presented. Thus, by means of the above-described relationship, through measuring the density of a given oil, its viscosity can be directly deduced.ª 2012 Elsevier Ltd. All rights reserved. IntroductionDiesel engines are being extensively utilized worldwide due to their high economic advantage and durability [1,2]. They have appealing features including robustness, high torque, and lower fuel consumption under certain conditions. According to Moron et al. [3] they are prevalent in sectors such as road and train transport, agriculture, military, construction, mining, maritime propulsion and stationary electricity production. Diesel engines can use several fuel types, including diesel fuel, straight vegetable oils (SVO), biodiesel e transesterified vegetable oil e and short chain alcohols. Diesel engines may also function with hybrid fuels, including SVO mixtures in different proportions with diesel or diesel/ ethanol. At the present time there is an increasing demand for energy, concerns about global warming and a growing interest in renewable energy sources; particularly in biofuels [4,5]. This is due to diminishing reserves and price instability of the world's petroleum fuel. These challenges are in part due to the diesel engines themselves. Consequently, it is an urgent matter to reduce hazardous pollutants that diesel engines emit such as NO x , CO, CO 2 and particulate matter (PM). According to Lee at al.[1] this can be achieved by using new combustion technology, by improving fuel characteristics and or by applying after-treatment technology. It is well known that utilizing biofuels with internal combustion engines may contribute to reduce greenhouse gas emissions [6]. Smallscale produced SVOs are considered attractive options for renewable fuel because of environmental benefits [7]. Smallscale use of vegetable oils is also considered an interesting option because they can be obtained from agricultural or industrial sources with very simple processing. This processing includes cold pressing and refining stages that avoid * Corresponding author. Tel.: þ34 938035300; fax: þ34 938031...

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-Recycled paper is extensively used worldwide. In the last decades its market has 1 expanded considerably. The increasing use of recycled paper in papermaking has led to the 2 production of paper containing several types of impurities. Consequently, wastepaper mills work is to present a fast and reliable system for identifying different paper types. Therefore, undesirable paper types can be refused, improving the performance of the paper 7 machine and the final quality of the paper manufactured. For this purpose two fast 8 techniques, i.e., Fourier transform mid-infrared (FTIR) and reflectance near-infrared 9 ( IR) were applied to acquire the infrared spectra of the paper samples. ext, four 10 processing multivariate methods, i.e., principal component analysis (PCA), canonical 11 variate analysis (CVA), extended canonical variate analysis (ECVA) and support vector 12 machines (SVM) were employed in the feature extraction -or dimension reduction-stage. 13Afterwards, the k nearest neighbors algorithm (k ) was used in the classification phase.

SUMMARYA new technique for induction motor fault detection and diagnosis is presented. This technique, which has been experimentally verified in stationary and non-stationary motor conditions, is based on the convolution of wavelet-based functions with motor stator currents. These functions are tuned to specific fault frequencies taking into account motor speed and load torque, thus considering variable operation conditions of the motor. Based on this technique an automatic system for fault diagnosis is also presented, which is suited for easy software implementation Q3 .

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